Machine punch having ejector pin retaining means



Nov. 13, 1962 E. M. JOHNSON 3,063,319

MACHINE PUNCH HAVING EJECTOR PIN RETAINING MEANS Original Filed Dec. 21, 1959 2 Sheets sheet 1 INVENTOR 6/121! [5. Jail/l5 0/:

BY f -oamj/y n ATTORNEY Nov. 13, 1962 E M. JOHNSON MACHINE PUNCH HAVING EJECTQR PIN RETAINING MEANS 2 Sheets-Sheet 2 Original Filed Dec. 21 1959 647/? ll. will??? ATTORNEY United States tic 3,063,319 MACHINE PUNCH HAVING EJECTOR PIN RETAINING MEANS Emil M. Johnson, Jamestown, N.Y., assignor to Producto Machine Company, Bridgeport, Conn., a corporation of Connecticut Continuation of application Ser. No. 860,856, Dec. 21, 1959. This application June 21, 1962, Ser. No. 206,121 2 Claims. (Cl. 83-128) This invention relates to machine tools and particularly to punches used to pierce openings of various shapes and sizes in sheet material. In one form the invention discloses a punch and mounting therefor of the general arrangement shown in my Patent No. 2,245,676, dated June 17, 1941. The punch is equipped with means for ejecting a punched-out slug after each perforating operation.

This application is a continuation of application Serial No. 860,856, filed December 21, 1959, in the name of Emil M. Johnson and now abandoned.

In the past, various means have been employed to eject slugs from punched material. Ejectors are essential to punching operations to assure the slug being driven beyond the pierced material into the relief of exit opening in the die. Without some positive means of ejection, it is possible for a slug to at least momentarily adhere to the piercing end of the punch, in which case the slug will be lifted from the die hole and deposited either under the stock or on top of it, depending on where the slug pulls free of the punch. In either case, damage to the punch, and/or die, and/or material can result in a successive operation. Effort is always made to keep the punch end and the material to be punched absolutely clean, but it often occurs that lubricant or foreign matter accumulates in a sufficient amount to create the condition wherein an ejector is needed.

Considering then that efficient punching operations require the use of ejectors, a problem arises as to how to handle the required periodic grinding or sharpening of the punch ends. In all cases wherein ejection of a slug is positive, springs or internally mounted pins so utilized must be displaced from the piercing ends. Many punch operations require multiple punches and often in close arrangement, thus the need to 'be able to quickly and easily displace these members is of prime importance. This, of course, takes into consideration the fact that many present machine items must be produced in large quantities at an economical cost. Thus, it may be assumed that repeated grinding of the punch piercing ends must take place many times during the manufacture of thousands of any given items.

The present invention is therefore primarily directed to a punch provided with a removable positive slu g ejector that is self-automatic in operation.

Another and most important object of the invention lies in the provision'of means by which the ejector pin may be quickly and easily inserted or removed, thus enabling, in multiple punches, a considerable saving in time in preparing such punches for operation or grinding.

A further object of the invention lies in the simplicity of construction, ease of assembly, and economy of parts by which to equip a punch with a positive slug ejector.

Oter objects and advantages of the invention will be apparent from a consideration of the following specification, taken in conjunction with the accompanying drawthe punches shown in FIG. 1, and discloses the normal or at-rest position of the ejector pin;

FIG. 3 is a view similar to FIG. 2 and shows the position of the ejector pin when the punch first contacts the material to be perforated;

FIG. 4 is a vertical sectional view showing one punch and die at the completion of a punching operation together with the position of a punched slug and the slug ejecting pin;

FIG. 5 is a vertical sectional view of a modification of the ejector pin releasable mount; and

FIG. 6 is a vertical sectional view of a further form of a releasable mount for the ejector pin.

Reference is now had to the drawing wherein the numeral 10 generally designates that portion of a press in which punches and dies are mounted. A conventional member 11 is adapted to mount a punch retaining plate 12, suitable studs 13 being provided for this purpose. Accurately aligned openings 14 and 16 are made in the member and plate 11 and 12, and dowels 17, inserted into these openings, serve to prevent relative lateral displacement of these parts. The plate 12 is generally provided with a plurality of openings 18 that are the diameter of the body portions 19 of punches 20. In the upper face of this plate are openings 22 which, atlhough of slightly larger diameter, are centered with the openings 18, thus providing annular shoulders 23. The head end or top 24 of each punch is intended to rest on the shoulder 23, the upper face thereof being flush with the top surface of plate 12. The portion 21 of each punch 20, beneath the body portion 19, is formed with a piercing end 25 of any desired shape and size.

Attention is now particularly directed to FIGS. 2 through 4 wherein one specific form of the invention is disclosed. Herein each punch 20 has a centered longitudinal opening 26 that extends from the anchored end of the punch to the vicinity of the tapered portion that terminates in the piercing end 25. From the lower end of opening 26, a very small diametered opening 27 extends to and is open at the piercing end 25. This difference in diameter of the concentric openings creates an annular shoulder 28. It is proposed to mount a holding or gripping chuck-like member 29 in the opening 26. This member, in the presently discussed modification, is shown as a metal cylinder and thus is rigid. It is intended to loosely fit the opening 26 and therefore has a diameter such that sufiicient clearance exists between it and the walls of opening 26 to provide free movement of the chuck-like member 29 within opening 26. One end of the chucklike member is enlarged to provide a collar 31 that may rest on the shoulder 28. From the collar, a small centered opening 32 extends at least part of the length of the cylinder and terminates in a closed or reduced diametered end 33-. A compression spring 34 may encircle the cylinder, one end thereof abutting the collar 31 and the other end, a plug 36 that is threaded into the upper end of the opening 26.

An ejector pin 37 is provided, being of the nature of a cylindrical rod of a diameter to freely move lengthwise of the opening 27. One end of this pin may be pointed, as at 38, and directly back of this point, the pin is shown to be of reduced diameter for a short distance, thus creating a head 39. From the head 39, the pin is preferably of uniform diameter to the ejector end 41.

Prior to assembling the punches with plate 12, a chuck 29, with spring 34, is placed in the opening 26 of each punch. The plug 36 is then threaded into the opening 13, the extent of the threads in the opening determining the location of the plug and the extent to which the spring 34 is compressed. It will be understood that a considerable space remains between the plug 36 and the adjacent end of the chuck 29. The punches may then be inserted in the openings 18, the heads 24 thereof being flush with the top surface of plate 12. Each pin 37 is now projected into the piercing end 25, head 38 first, and is freely movable toward the opening 32 in the chuck 29. It is important to note that the chuck is either formed from material that is slightly radially expandable or ineludes means by which the opening 32 may be expanded under slight pressure. The head 39 is now pressed into frictional engagement with the walls of the opening 32 and, during this assembly, the chuck moves and compresses spring 34 to a point where the closed end of the chuck engages the plug 36. At this point, further inward movement of the pin seats the point 38 against end 33 of the chuck. When pressure on the pin is released, spring 34 causes the chuck and pin, now operating as one, to assume the at-rest position shown in FIG. 2. The pin length is such that it now extends a slight but predetermined distance beyond the piercing end 25.

Referring to FIG. 3, it will be noted that on contact of the punch with the material to be perforated, the pin end has moved into a flush position with respect to the end 25 and the chuck is in a cocked position due to compression of spring 34. When the punch has completely perforated the material, a free slug is produced and the ejector pin 37, under impulse of spring 34, forces this slug downwardly through an exit opening in the die. This phase of the punching operation is illustrated in FIG. 4. As mentioned above, repeated use of punches dulls them and they are required to be re-sharpened by grinding. The ejector pins 37 would, obviously, interfere with a grinding operation and must therefore be removed. By reason of the structure of the present invention, pin removal merely involves either grasping and pulling each pin, or using a suitable tool for the purpose of removing the head 38 from the chuck 29, and, of course, when the head 38 is withdrawn from the chuck, it is readily removable from the punch. Following grinding the piercing ends 25, the pins may be re-inserted in the manner above described.

Now referring to FIG. 5, there is disclosed a modification of the gripping member or chuck 29. Herein a splitsided tubular metal member 43 is provided. One end 44 is closed to seat the end 38 of the ejector pin. The free sides 46 of this member terminate in lateral flanges 47. These flanges, in function, are the equivalent of the collar 31 above described. Further, by splitting a metal tube, the radially expandable action of the chuck 29 is duplicated. However, since no portion of this chuck extends appreciably beyond the seat for the end 38, it is proposed to provide a rod-like extension 48 inwardly of the plug 36. The length of this extension, or the depth to which the plug 36 is threaded, provides approximately the same operative travel as described for the chuck 29.

A further modification of the chuck 29 is shown as chuck 49 in FIG. 6. Herein it is proposed to combine the ejector pin holding chuck with a spring. In other words, chuck 29, in this instance, and spring 34 are produced as one element. This is accomplished by coiling a wire in such manner as to provide a socket 51 or somewhat confined area for the head 39 of pin 37. At the place of abutment with the point 38, the coil is expanded and enlarged to provide a spring 52 which is the equivalent of spring 34. Of course, the seat for spring 52, remote from socket 51, is readily determined by the location of plug 36, extension 48, or both,

From the foregoing, it will be understood that the present invention provides unique means for readily mounting and releasing an ejector pin in punches and that variations of the several modifications herein shown and described may be made without departing from the spirit and scope of the invention as set out in the annexed claims.

What is claimed is:

1. In a die punch adapted to include a plurality of closely spaced body elements each having walls forming an axial bore terminating in a cutting end and a threaded counterbore therein with a shoulder therebetween, a rigid tube-like chucking element having an outside diameter such that sufficient clearance exists between it and the walls of said counterbore to provide free movement thereof within said counterbore and adapted to rest against said shoulder, said rigid chucking element having internal walls forming an axial pin receiving recess therein, and said chuck walls having the capability of slight radial expansion and contraction; a coiled spring within said counterbore having one end in cooperating position with said chucking element; a plug threaded into said counterbore for engagement with the end of said coiled spring opposite that in cooperating position with said chucking element; and pin means slidingly mounted within said bore and having an end constructed in a manner facilitating its insertion in and withdrawal from the pin receiving recess within said chucking element from the cutting end of said body element.

2. In a die punch adapted to include a plurality of closely spaced body elements each having walls forming an axial bore terminating in a cutting end and a threaded counterbore therein with a shoulder therebetween, a rigid tube-like chucking element having an outside diameter such that sufficient clearance exists between it and the walls of said counterbore to provide free movement thereof within said counterbore and adapted to rest against said shoulder, said rigid chucking element having internal walls forming an axial pin receiving recess therein, and said chuck walls having the capability of slight radial expansion and contraction; a coiled spring within said counterbore having one end in cooperating position with said chucking element; a plug threaded into said counterbore for engagement with the end of said coiled spring opposite that in cooperating position with said chucking element; pin means slidingly mounted within said bore and having an end constructed in a manner facilitating its insertion in and Withdrawal from the pin receiving recess within said chucking element from the cutting end of said body element; and means between said chucking element and plug for limiting the extent of compression of said spring.

References Cited in the file of this patent UNITED STATES PATENTS 87,062 Papine Feb. 16, 1869 128,783 Blondel July 9, 1872 190,747 Lepine Mar. 15, 1877 676,053 Sporleder June 11, 1901 1,563,574 Jensen Dec. 1, 1925 1,589,127 Deveault June 15, 1926 1,806,266 Sawle May 19, 1931 1,887,085 Ehrlick Nov. 8, 1932 1,940,438 Stowell Dec. 19, 1933 2,088,118 Schillo July 27, 1937 2,245,676 Johnson June 17, 1941 2,316,650 Klopfenstein I Apr. 13, 1943 2,786,528 Wick Mar. 26, 1957 2,917,960 Gargrave Dec. 22, 1959 3,019,683 Welbaum Feb. 6, 1962 FOREIGN PATENTS 900,405 Germany Dec. 28, 1953 

